One or more actors, such as humans, objects and robots, can move throughout an environment, such as the interior of part or all of a building and/or its surrounding outdoor regions, to perform tasks or otherwise utilize the space. For example, humans, objects and robots can be used together to manufacture complex machinery, such as automobiles, airplanes, machine tools, and even other robots. Other environments may exist where humans, objects and robots can be used together. In manufacturing environments, passive indicators, such as cones, flags or signage, have been employed to alert human actors. Such passive indicators depend upon visual contact from an individual, but when an individual does not perceive the passive indicator the purpose is defeated. Further cut-off switches and proximity sensors have been employed for operator-controlled object actors and automated robot actors, but these are specific to particular applications and are not modular or expandable.